The famous US group, fronted by singers Will.i.am and Stacy Fergie Ferguson, will be flown out to perform as part of the three-day celebrations being held at the 13th Century Odescalchi Castle, near Rome, over the August bank holiday weekend. The event will see 300 guests as 22-year-old Petra exchanges nuptial vows with businessman James Stunt, 26.

The wedding celebrations are set to dwarf the sumptuous $1.6 million party Bernie laid on at London’s Battersea Power Station to mark Petra’s engagement in May. The no-expense-spared event is being handled by international party-planners Bentley’s Entertainments. The firm specialises in luxury wedding parties and claims to excel in sourcing and producing the ideal act, artist or performance to suit any event and location.

It’s the second high-profile private booking for the group, who have sold more than 56 million albums worldwide. In December,The Black Eyed Peas, were flown out to the Caribbean island of St Barts by Russian oligarch and Chelsea Football Club owner Roman Abramovich to perform at his New Year’s Eve party.